Prediction models of grip strength in adults above 65 years using Korean National Physical Fitness Award Data from 2009 to 2019.

PURPOSE: We aimed to determine the best machine learning (ML) regression model for predicting grip strength in adults above 65 years using various independent variables, such as body composition, blood pressure, and physical performance. METHODS: The data comprised 107,290 participants, of whom 33.3% were male and 66.7% were female in Korean National Fitness Award Data from 2009 to 2019. The dependent variable was grip strength, which was calculated as the mean of right and left grip strength values. RESULTS: The results showed that the CatBoost Regressor had the lowest mean squared error (M [Formula: see text] SE:16.659 ± 0.549) and highest R2 value (M [Formula: see text] SE:0.719 ± 0.009) among the seven prediction models tested. The importance of independent variables in facilitating model learning was also determined, with the Figure-of-8 walk test being the most significant. These findings suggest that walking ability and grip strength are closely related, and the Figure-of- 8 walk test is a reasonable indicator of grip strength in older adults. CONCLUSION: The findings of this study can be used to develop more accurate predictive models of grip strength in older adults.

Effect of Resistance Training with Different Set Structures on Neurotrophic Factors and Obesity-Related Biomarkers in Middle-Aged Korean Women with Obesity.

This 12-week study investigates the effects of resistance training with different set structures on the plasma levels of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), and obesity-related markers in middle-aged Korean women with obesity. A total of 40 middle-aged women with obesity (mean age, 59.87 ± 2.80 years) were enrolled in this study; only 31 women were able to complete the 12-week exercise period. The participants were randomly divided into the following four groups: control (CON, n = 8), drop set system (Drop, n = 8), descending set system (Descend, n = 7), and ascending set system (Ascend, n = 8). Body composition was recorded, and blood samples were obtained and evaluated before and after the 12-week exercise period intervention. Two groups showed no significant differences in body weight, body fat percentage, and body mass index before and after the 12-week exercise period. However, significant differences were observed in the blood levels of BDNF, NGF, adiponectin, leptin, and glucagon-like peptide-1 (GLP-1). BDNF and NGF showed significant differences in both time and interaction effects. Post hoc analysis revealed that the Drop group had higher BDNF and NFG levels than those of the Ascend and CON groups, while there was a significant increase in the levels of these biomarkers in the Descend and Drop groups in the time comparison. Adiponectin levels also showed significant differences in both time and interaction effects. Post hoc analysis revealed that the Drop and Descend groups had higher adiponectin levels than those of the CON group. Leptin levels decreased significantly in the Descend and Drop groups over time. GLP-1 levels showed no significant differences between the groups; however, there were significant differences in both time and interaction effects. Post hoc analysis revealed that the Drop group had lower GLP-1 levels than those of the CON group. This study suggests that resistance training with different set structures can have varying effects on the blood levels of different biomarkers in middle-aged women with obesity. These findings have implications for exercise prescription, and may provide insights into the mechanisms underlying the beneficial outcomes of resistance training in middle-aged Korean women with obesity.

Treadmill exercise improves spatial learning ability by increasing cell proliferation in offspring born to maternal rats receiving stress during pregnancy.

Prenatal stress causes learning deficits by inhibiting neurogenesis in the hippocampus. We studied the effects of maternal treadmill running or offspring treadmill running on the spatial learning ability of adolescent offspring rats or adult offspring rats born to maternal rats that received stress during pregnancy. For this study, spatial learning ability was measured by radial 8-arm maze task. Immunohistochemistry for 5-bromo-2'-deoxyuridine and Western blot for brain-derived neurotrophic factor (BDNF), tyrosine kinase B (TrkB), Bcl-2-associated X protein (Bax), and B-cell lymphoma 2 (Bcl-2) were also conducted. Stress was induced by exposing pregnant rats to hound in an enclosed room. Maternal treadmill running or treadmill running of offspring improved spatial learning ability of adolescent and adult offspring rats born to maternal rats receiving stress during pregnancy. Maternal treadmill running or treadmill running of offspring increased hippocampal cell proliferation of adolescent and adult offspring rats born to maternal rats receiving stress during pregnancy. Maternal treadmill running or treadmill running of offspring increased BDNF and TrkB expression in the hippocampus of adolescent and adult offspring rats born to maternal rats receiving stress during pregnancy. Maternal treadmill running or treadmill running of offspring inhibited Bax expression and increased Bcl-2 expression in the hippocampus of adolescent and adult offspring rats born to maternal rats receiving stress during pregnancy. Mother's exercise during pregnancy or child's exercise after childbirth can improve the spatial learning ability deteriorated due to stress during pregnancy.

Cardiac adaptation to exercise training in health and disease.

The heart is the primary pump that circulates blood through the entire cardiovascular system, serving many important functions in the body. Exercise training provides favorable anatomical and physiological changes that reduce the risk of heart disease and failure. Compared with pathological cardiac hypertrophy, exercise-induced physiological cardiac hypertrophy leads to an improvement in heart function. Exercise-induced cardiac remodeling is associated with gene regulatory mechanisms and cellular signaling pathways underlying cellular, molecular, and metabolic adaptations. Exercise training also promotes mitochondrial biogenesis and oxidative capacity leading to a decrease in cardiovascular disease. In this review, we summarized the exercise-induced adaptation in cardiac structure and function to understand cellular and molecular signaling pathways and mechanisms in preclinical and clinical trials.

The Effects of 12 Weeks of a Combined Exercise Program on Physical Function and Hormonal Status in Elderly Korean Women.

Aging causes a decline in physical function and hormonal balance. Exercise can improve these parameters. However, the beneficial effects of a combined exercise program (Korean dance and yoga) on physical function and hormonal status in elderly women remain unknown. This study aims to investigate the effects of a 12-week combined exercise program on balance, flexibility, muscle strength, and hormonal status in elderly Korean women. Twenty-five healthy elderly women were recruited and randomly divided into the control (CON) and exercise (EXE) groups. The EXE group underwent the combined exercise program (60 min/day and 3 times/week) for 12 weeks. The two groups did not differ in body weight, lean body mass, fat mass, body fat percentage, or body mass index at baseline or in the changes following the experimental conditions. A significant time × group interaction was detected for anterior and posterior dynamic balance, static balance, and growth hormone (GH). After the combined exercise program, anterior dynamic balance, posterior dynamic balance, static balance, flexibility, muscle strength, GH, dehydroepiandrosterone-sulfate, and estrogen significantly increased in the EXE group compared to the CON group. In conclusion, the combined exercise program contributed to improvements in overall health, including physical function and hormonal status, in elderly Korean women.

Potential for foot dysfunction and plantar fasciitis according to the shape of the foot arch in young adults.

This study investigated potential for foot dysfunction and plantar fasciitis according to the shape of the foot arch in young adults. Fifty-two participants were required for the present study design to achieve 80% power, 0.8 effect size (η2), and an alpha level of 0.05. This study recruited 52 young adults (30 men and 22 women). All participants voluntarily agreed to participate in the study after hearing explanations about the purpose and process of the study. They were divided into two groups of 26 according to the shape of foot with and without flat foot using the navicular drop test. The participants were measured the foot function index (FFI), range of motion (ROM) of ankle, and four-way ankle strength. Additionally, the thickness of the plantar fascia was measured using ultrasonography. Intraclass correlation coefficient (ICC) was used to verify the inter- and intrarater reliability of ultrasonography. The inter- and intrarater reliability was excellent (ICC2,1=0.88, ICC3,1=0.93). There were significant differences in dorsi-flexion of ankle ROM, FFI, dorsi-flexion and eversion of ankle strength, and the thickness of the plantar fascia between the two groups (P<0.05). Based on the results, the group with flat foot may gradually generate potential of the foot dysfunction and plantar fasciitis. Therefore, the interventions are necessary to improve the foot dysfunction and plantar fasciitis in people with flat foot.

Ursolic acid supplementation decreases markers of skeletal muscle damage during resistance training in resistance-trained men: a pilot study.

Ursolic acid (UA) supplementation was previously shown to improve skeletal muscle function in resistance-trained men. This study aimed to determine, using the same experimental paradigm, whether UA also has beneficial effects on exercise-induced skeletal muscle damage markers including the levels of cortisol, B-type natriuretic peptide (BNP), myoglobin, creatine kinase (CK), creatine kinase-myocardial band (CK-MB), and lactate dehydrogenase (LDH) in resistance-trained men. Sixteen healthy participants were randomly assigned to resistance training (RT) or RT+UA groups (n=8 per group). Participants were trained according to the RT program (60~80% of 1 repetition, 6 times/week), and the UA group was additionally given UA supplementation (450 mg/day) for 8 weeks. Blood samples were obtained before and after intervention, and cortisol, BNP, myoglobin, CK, CK-MB, and LDH levels were analyzed. Subjects who underwent RT alone showed no significant change in body composition and markers of skeletal muscle damage, whereas RT+UA group showed slightly decreased body weight and body fat percentage and slightly increased lean body mass, but without statistical significance. In addition, UA supplementation significantly decreased the BNP, CK, CK-MB, and LDH levels (p<0.05). In conclusion, UA supplementation alleviates increased skeletal muscle damage markers after RT. This finding provides evidence for a potential new therapy for resistance-trained men.

Ursolic Acid-induced elevation of serum irisin augments muscle strength during resistance training in men.

Ursolic acid (UA), a type of pentacyclic triterpenoid carboxylic acid purified from natural plants, can promote skeletal muscle development. We measured the effect of resistance training (RT) with/without UA on skeletal muscle development and related factors in men. Sixteen healthy male participants (age, 29.37±5.14 years; body mass index=27.13±2.16 kg/m(2)) were randomly assigned to RT (n=7) or RT with UA (RT+UA, n=9) groups. Both groups completed 8 weeks of intervention consisting of 5 sets of 26 exercises, with 10~15 repetitions at 60~80% of 1 repetition maximum and a 60~90-s rest interval between sets, performed 6 times/week. UA or placebo was orally ingested as 1 capsule 3 times/day for 8 weeks. The following factors were measured pre-and post-intervention: body composition, insulin, insulin-like growth factor-1 (IGF-1), irisin, and skeletal muscle strength. Body fat percentage was significantly decreased (p<0.001) in the RT+UA group, despite body weight, body mass index, lean body mass, glucose, and insulin levels remaining unchanged. IGF-1 and irisin were significantly increased compared with baseline levels in the RT+UA group (p<0.05). Maximal right and left extension (p<0.01), right flexion (p<0.05), and left flexion (p<0.001) were significantly increased compared with baseline levels in the RT+UA group. These findings suggest that UA-induced elevation of serum irisin may be useful as an agent for the enhancement of skeletal muscle strength during RT.

Effects of aged garlic extract and endurance exercise on skeletal muscle FNDC-5 and circulating irisin in high-fat-diet rat models.

BACKGROUND/OBJECTIVES: Irisin, a newly identified hormone, is associated with energy homeostasis. We investigated whether aged garlic extract (AGE) and exercise training intervention could improve body weight, insulin sensitivity, skeletal muscle fibronectin domain containing protein 5 (FNDC-5) levels, and plasma irisin in high-fat diet (HFD). MATERIALS/METHODS: Male Sprague Dawley rats were fed a ND (normal diet, n = 5) or HFD (n = 28) for 6 weeks. After 6 weeks, all rats were divided into 5 groups for the next 4 weeks: ND, (normal diet, n = 5), HFD (high-fat diet, n = 7), HFDA (high-fat diet + aged garlic extract, n = 7), HFDE (high-fat diet + exercise, n = 7), and HFDEA (high-fat diet + exercise + aged garlic extract, n = 7). Exercise groups performed treadmill exercises for 15-60 min, 5 days/week, and AGE groups received AGE (2.86 g/kg, orally injected) for 4 weeks. RESULTS: Significant decreases in body weight were observed in the ND, HFDE, and HFDEA groups, as compared with the HFD group. Neither intervention affected the masses of the gastrocnemius muscle or liver. There were no significant differences in glucose levels across the groups. The homeostatic model assessments of insulin resistance were significantly higher in the HFD group, as compared with the ND, HFDA, HFDE, and HFDEA groups. However, skeletal muscle FNDC-5 levels and plasma irisin concentrations were unaffected by AGE or exercise in obese rats. AGE supplementation and exercise training did not affect skeletal muscle FNDC-5 or plasma irisin, which are associated with insulin sensitivity in obese rats. CONCLUSION: Our results suggest that the protection against HFD-induced increases in body fat/weight and insulin resistance that are provided by AGE supplementation and exercise training may not be mediated by the regulation of FNDC-5 or irisin.

Corrigendum to: Ursolic Acid-Induced Elevation of Serum Irisin Augments Muscle Strength During Resistance Training in Men.

[This corrects the article on p. 441 in vol. 18, PMID: 25352765.].

Aged garlic extract enhances exercise-mediated improvement of metabolic parameters in high fat diet-induced obese rats.

Aged garlic extract (AGE) is known to have a protective effect against immune system, endothelial function, oxidative stress and inflammation. We examined the effects of exercise with and without aged garlic extract administration on body weight, lipid profiles, inflammatory cytokines, and oxidative stress marker in high-fat diet (HFD)-induced obese rats. Forty-five Sprague-Dawley rats were fed either a HFD (HFD, n = 40) or a normal diet (ND, n = 5) for 6 weeks and thereafter randomized into ND (n = 5), HFD (n = 10), HFD with AGE (n = 10), HFD with Exercise (n = 10), or HFD with Exercise+AGE (n = 10) for 4 weeks. AGE groups were administered at a dose of 2.86 g/kg·body weight, orally. Exercise consisted of running 15-60 min 5 days/week with gradually increasing intensity. AGE (P < 0.01), Exercise, and Exercise+AGE (P < 0.001) attenuated body weight gain and food efficiency ratio compared to HFD. Visceral fat and liver weight gain were attenuated (P < 0.05) with all three interventions with a greater effect on visceral fat in the Exercise+AGE than AGE (P < 0.001). In reducing visceral fat (P < 0.001), epididymal fat (P < 0.01) and liver weight (P < 0.001), Exercise+AGE was effective, but exercise showed a stronger suppressive effect than AGE. Exercise+AGE showed further additive effects on reducing visceral fat and liver weight (P < 0.001). AGE significantly attenuated the increase in total cholesterol and low-density lipoprotein-cholesterol compared with HFD (P < 0.05). Exercise+AGE attenuated the increase in triglycerides compared with HFD (P < 0.05). Exercise group significantly decrease in C-reactive protein (P < 0.001). These results suggest that AGE supplementation and exercise alone have anti-obesity, cholesterol lowering, and anti-inflammatory effects, but the combined intervention is more effective in reducing weight gain and triglycerides levels than either intervention alone.